Programmable exercise machine

ABSTRACT

An exercise machine has automatic and programmable resistance selection apparatus with vertically aligned weights that are selectable by rotably engaging a lift pin to select each weight stack. The exercise machine further includes a control panel from which the number of weights to be lifted can be ordered by the user. Alternatively the number of weights being lifted may be programmed from a remote location.

[0001] This application claims the benefit of U.S. Provisional patentapplication Ser. No. 60/213839 filed Jun. 23, 2000, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an exercise machine that can beadjusted easily for various resistance levels. More particularly, thisinvention relates to remotely adjustable or programmable resistanceexercise machines.

[0004] 2. Description of Related Art

[0005] Physical exercise for strength training or bodybuilding consistsof a sequence of movements that begins at a rest position, provides astress on a particular muscle or group of muscles for a period of timeand then ends at the rest position.

[0006] There are at least three types of machine-based exercises:

[0007] 1. Isokinetic—The machine is programmed to pace the cycle at aconstant speed. If the user moves faster, he or she encounters a higherresistance. If the user moves slower, he or she encounters lessresistance. This type of exercise is currently not favored for musclebuild-up.

[0008] 2. Isometric—The user exerts a force with no movement (e.g.against a wall). This type of exercise is used in physical therapy wheredamage to the ligaments prohibits large movements. It is not applicablefor general muscle building.

[0009] 3. Isocentric—The machine provides a constant force or torque asa resistance. This is currently the most desirable type of exercise formuscle building.

[0010] Various methods of generating constant resistance for machinesthat can be used to perform isocentric exercises have been suggested inthe art. These include machines relying on magnetic clutch resistance,direct DC motor resistance, hydraulic and pneumatic resistance (bothpassive resistance and work against active pressure sources), springs,weights and combinations of these technologies.

[0011] Market research indicates a strong preference by users formachines that use weights as the active resistance element. The smoothand even operation of well-designed weight machines has been the key totheir acceptance. Some advanced technology machines based on directmotor drive, as illustrated by U.S. Pat. No. 5,020,794, Englehardt etal., have gained limited acceptance in upscale professional gyms.However, the inherent cost of the components, the electronics and thepower requirements to operate such machines have made them uneconomicalfor the home market.

[0012] While selectable weight stacks, and even motor-driven selectableweight stacks, have been disclosed in the prior art, they suffer fromseveral disadvantages.

[0013] U.S. Pat. No. 5,876,313 (Krull) shows a radial weight selectorincorporated into exercise machines. The Krull patent shows selectorpins engaged such that all the weights that are selected are engagedsimultaneously. Although Krull further demonstrates that a single weightstack is not adequate to cover the range of resistance that is requiredfor an exercise machine and illustrates a dual weight stack havingweights that are placed side by side to achieve a full weight range,Krull utilizes a bulky and expensive design that requires four guiderods. The rods must be manufactured of a strong metal, be preciselymachined to be straight, then mounted precisely. Further, each weightmust have low-friction linear bearings to allow the weights to movesmoothly along the axis that is dictated by the guide rods. The twostacks placed side-by side require a large footprint. The combinedstacks are not likely to fit in the footprint of most common weightexercise machines, thus requiring a complete redesign of such machines.

[0014] Krull teaches a selector assembly that is rotated either by amotor, which is mounted on the selector, or by dropping the assemblyonto a set of gears that are rotated mechanically or by a motor. Thefirst solution requires that the motors be lifted along with theweights. This approach is undesirable because of the extra weight of themotors, motor stress, and the difficulties associated with providingpower to a reciprocating motor. The second solution, where the selectorengages a set of gears in the base, requires a precise alignment of thegears and will likely cause the selector to be misaligned after thecompletion of a number of cycles during which the selector may berotated and can ultimately cause a critical failure.

[0015] Other Krull patents disclose exercise machines that addressweight selection mechanisms. These also suffer from variousdisadvantages. These patents include U.S. Pat. Nos. 5,935,048, 5,944,642and 6,033,350.

[0016] The patents to Lowe (U.S. Pat. No. 6,117,049), Scaramucci (U.S.Pat. No. 6,015,367) and La Lanne (U.S. Pat. No. 3,647,209), as well asU.S.S.R. Patent 1,389,789, are further examples of selectable weightstacks. The La Lanne patent discloses a radial weight selectionmechanism; the Scaramucci patent discloses a weight mechanism selectedby hooks; the Lowe patent discloses a motor-driven mechanism driving athreaded shaft to select the weights; and the U.S.S.R. patent disclosesspring-load radial plungers for the weight selection.

[0017] These patents suffer from the disadvantages of providingrelatively complex mechanisms. Moreover, the Lowe patent, whichdiscloses a motor-driven selection mechanism, suffers from the furtherdisadvantage of requiring the motor to be mounted on the weights and forthe motor to move, as the weights are lifted.

[0018] As will be explained hereinafter, the present invention combinesthe use of weights with the ability to remotely select the weights, forexample by a motor-driven selector mechanism, while at the same timeavoiding the disadvantages of the prior art. The technology also lendsitself to mechanized selection of the weight using flexible cables andmechanical dials. An application for such a mechanism is found incommonly available exercise machines where direct access to the weightstack is limited due to the elaborate structure of these machines.Because the resistance is generated by the pull of gravity on theweights, the design is energy efficient and is only marginally moreexpensive than a conventional, pin-selected weight stack machine.

SUMMARY OF THE INVENTION

[0019] An object of this invention is to provide an exercise machinehaving remote and programmable resistance selection.

[0020] A further object of this invention is to provide an exercisemachine having a motor-driven selector for selecting the weights inwhich the motor does not move with the weights as the weights are raisedor lowered.

[0021] Another object of this invention is to provide an exercisemachine with nestable, multiple weight stacks that are selectable byengaging a single lift pin pair to select each weight of a weight stack.

[0022] The exercise machine of this invention uses weights as aresistance against which the various muscles are exercised. Although notlimited to a particular market, the goal is to provide a machine thatcan be economically offered to the home market while still providing theadvantages of more expensive exercise machines. One advantage is toprovide an exercise machine with programmable resistance capabilities.In an exercise machine with programmable resistance capabilities, theuser can select the desired resistance through a panel from the seat. Acomplete workout can be pre-programmed and the user follows the machinein “Automatic” mode very much like working with a personal trainer. Byautomating the resistance selection, the exercise machine can beprogrammed remotely (for example, from a personal computer or from theInternet). This allows the exercise machine to become part of acomprehensive regimen of diet and exercise, which may be planned byexperts (or expert software). The exercise machine with programmableresistance capabilities also allows the actual performance of the userto be fed back to the regimen planner for follow-up modification or todisplay the actual execution in comparison with the original plan.

[0023] To accomplish these and other objects an electronicallyselectable exercise machine has a coupling mechanism such as a handleconnected to a cable at its proximal end arranged to transfer aresistance to a user of the electronically selectable exerciseapparatus. The machine includes a lifting plate connected to the cableat its distal end and one or more sets of weights arranged in stacks. Amotor-driven selector is provided which is arranged to engage one weightin each stack. Since the weights are stacked on each other, if theselected weight is lifted, all the other weights of that stack disposedabove the selected weight are lifted simultaneously by the plate. Themotor is located such that it does not move with the weights as theweights are raised or lowered. In a particularly advantageousarrangement, two sets of stacks are provided which are nested togetherto reduce space. The weights of each stack can reciprocate verticallyalong two guide rods.

[0024] Each weight of each stack has an opening or cavity receiving oneof the guide rods. A selector in the form of a cylindrical member isalso disposed in this opening.

[0025] The selector also includes two sets of lifting pins. The weightshave tabs, each weight of a particular set having a uniquely orientedset of tabs. The selector has a set of unique angular positions, thenumber of positions being equal to the number of weights in a stack plusone. In each of its positions except one, the selector then engages thetabs of one of the weights. As the selector is lifted, it lifts with itthe weight corresponding to the current position of the selector and allthe weights disposed above that particular tab. The selector is rotatedto a predetermined angular position when the stacks are at the bottom ofthe equipment. The rotation is accomplished by using stationary motorsthat may be controlled locally or remotely.

[0026] The exercise machine has a programmable control unit incommunication with the motors, and a display that is used to show thecurrent weight setting of the machine and provide other data regardingthe operation of the machine. The control unit further includes an inputkeypad to allow the input of a schedule of resistances provided to saidusers, and a network interface in communication with a computing systemto record a user's progress in exercising and to calculate futureexercise regimen.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a side view of a weight lifting machine of thisinvention.

[0028]FIG. 2 is a cut away plan view of the weight stack used in themachine of FIG. 1 taken along line 2-2.

[0029]FIG. 3 is a perspective view of the weight lifting machine of thisinvention.

[0030]FIG. 4 is a cut away view of the weight stack of the machine ofFIG. 1 taken along line 4-4.

[0031]FIG. 5 illustrates an enlarged perspective view of the weightstack and details of the selector mechanism.

[0032]FIG. 6 is a top view of the secondary weight stack of thisinvention.

[0033]FIG. 7 is a cut away view of the weight stack of FIG. 6 takenalong line 7-7.

[0034]FIG. 8 illustrates the weight stack with one large weight plateand two small weight plates selected according to this invention.

[0035]FIG. 9 illustrates the weight stack with five large weight platesand six small weight plates selected according to this invention.

[0036]FIG. 10 is a block diagram of the electronic control and displaycircuit for the programmable weight lifting machine of this invention.

[0037]FIG. 11 is a cross sectional view of a weight plate showing thelifting ring and lift tabs of this invention.

[0038]FIG. 12 is a diagram of a lift tab of this invention.

[0039]FIG. 13 is a perspective view of the weight selector of thisinvention.

DETAILED DESCRIPTION OF THE INVENTION

[0040]FIG. 1 shows an exercise machine 100 of this inventionincorporating a selectable weight stack 101. The user pulls on handle105 that is connected at the proximal end of a cable or similarelongated member 110 to the weight stack 101. The machine 100 furtherincludes a control unit 102 having a user display panel 103. The controlunit is connected to a drive unit (discussed in more detail below, inconjunction with FIG. 3) that is used to select the “weight” to belifted. Usually, at least some of the weights of the weight stack 101 inaccordance with a choice made by the user will be selected. However,where only minimal weight is desired, the user may select only the topplate of the weight stack and not the weights, per se.

[0041] As shown in more detail in FIG. 3, the machine 100 includes avertical post 106 with a longitudinal guide bar 119. The post 106supports a horizontal plate 108. Plate 108 supports two pulleys 117,118. The machine 101 further includes a base 158 which supports the post106 as well as two vertical guide rods 111, 112.

[0042] The weight stack 101 consists of weights which are selectivelycoupled to a plate 113 as discussed in more detail below. The stack 101is arranged and constructed so that it is movable vertically up or downalong the two guide rods 111, 112 and guide bar 119. The cable 110 istrained over pulleys 117 and 118 and then passes through a hold in plate108. It then extends downwardly between the guide rods 111 and 112 andis attached to the plate 113 of stack 101 by a hook 114 at the distalend of the cable. As the user pulls on cable 110 with handle 105, thecable 110 forces the plate 113 and any weights attached thereto to rise.Thus the force exerted by the user on the handle is determined by thenumber of weights attached to the plate 113 (as well as the weight ofthe plate 113 itself). As the user allows the handle to move back towardthe plate 108, the plate 113 and weights attached thereto are loweredtoward the base 158. Bushings 115 and 116 attached to plate 113 areprovided and act as linear bearings, to reduce the friction between theguide rods 111 and 112 and the lift plate 113, as the weight stack israised and lowered.

[0043]FIG. 2 provides a horizontal cross sectional view of the weightstack 101, looking downwardly just below plate 113 and FIG. 4 shows avertical cross sectional view of the weight stack 101. As can be seen inthese Figures, the weight stack 101 includes plate 113, a set orplurality of vertically aligned outer weights 121 forming an outerweight stack, a set or plurality of vertically aligned inner weights 122forming an inner weight stack and two selectors 141, 150. The selectors141, 150, disposed in cavities or passageways in the weights (one suchcavity or passageway being shown in FIG. 7), are used to selectivelycouple some or all of the outer and inner weights 121, 122 to the plate113.

[0044] As seen more clearly in FIG. 2, each outer weight 121 has a roundopening for a corresponding inner weight 122. Both weights 121, 122 arefree to move vertically, independently of each other, along rods 111,112. Both weights 121 and 122 are prevented from rotating about theirrespective vertical axes by guide bar 119, guide notch 129 (formed inthe inner weight 122) and guide notch 129A (formed in outer weight 121).While the inner weights 122 are generally circular in shape, each outerweight has a somewhat oblong configuration, with straight sides 502 andcurved ends 504 and 506. End 504 defines a greater radius of curvaturethan end 506. This shape advantageously presents a center of gravity forthe weight at guide 111, thereby preventing binding as the outer weightsare raised or lowered about the guide.

[0045] As seen in FIG. 4, selector 150 has at its top end a lip 128which rests on bushing 116. The bushing 116 is made of a low-frictionmaterial such as nylon, and allows the selector 150 to rotate freelywith respect to the lift plate 113 and guide rod 112. Selector 141 has asimilar lip 115A resting on bushing 115. Bushing 115 is also made ofnylon and allows the selector 141 to rotate with respect to the plate113 and guide rod 111. Lip 128 is positioned to abut the top surface ofplate 113. Accordingly, as plate 113 is raised by a user pulling oncable 110, the plate lifts selector 150 which, in turn, allows the userto raise the weights selected by selector 150.

[0046] Details of the selector mechanism used to select the weightscoupled to the plate 113 are now described in conjunction with theFigures. As shown in FIG. 13, the selector 150 consists of a cylindricalwall 150A on which there are mounted an array of lift pins 142. Thearray is partitioned into two sets of diametrically opposed pins 144 aand 144 b. All pins 144 a are vertically aligned and all pins 144 b arevertically aligned along the surface 150A as shown. In addition each pin144 a is aligned horizontally with a respective pin 144 b. The verticalspacing between the pins 144 in the array 142 matches the height of theweights 121,122 in the stack 101.

[0047] Each inner weight 122 includes a tab ring 125. As shown in FIGS.5 and 11 the tab rings 125 are press-fit into holes 121A of therespective weights 122 from their respective underside. Due to a slighttaper (shown somewhat exaggerated in FIG. 11), each ring 125 is wedgedonto the respective weight 122. Each tab ring is provided with two tabs126 a, 126 b diametrically opposed to each other. The tab ring 125defines a hole 126 c for the selector 150.

[0048] When the selector 150 is inserted through the hole 126 c, twoappropriately aligned lift pins 144 a, 144 b register with the tabs 126a and 126 b on tab-ring 125. Therefore, when the selector 150 moves up,it lifts the weight 122 with it through the tabs 126 a, 126 b.

[0049]FIG. 12 shows details of the tabs 126 a and 126 b of FIGS. 5 and11. Tab 126 a is formed of a structural material such as steel to beable to support the entire weight stack 101. For example, this weightmay be 300 lbs. or greater. To support the weight of the stack thelifting tab should have a width W₁ of approximately 1.5 times thediameter of the selector pin. For example, a 300-lb. weight stackrequires a 0.250″ selector pin, thus the lift tab 126 a is approximately0.4″. To make the lift pins 144 a, 144 b self-securing, a seating notch128 is formed in the lifting tab 126. The seating notch 128 must be wideenough to accommodate any tolerances in the alignment of the selectorpin. Therefore, the seating notch 128 should be at least 20% larger indiameter than the selector pin. In the case described above the width W₂of the notch is approximately 0.3″ in diameter. The outer weights 121are provided with identical tab rings and tabs to match lift pins onselector 141.

[0050]FIG. 7 provides a sectional view of inner weight stack 129comprised of inner weights 122, each inner weight 122 being nested in acorresponding outer weight 121 (see FIG. 2). As can be seen in FIG. 7,the tabs 126 a of each inner weight 122 are angularly offset from eachother.

[0051] More specifically, when observed from the top, the tabs 126 a and126 b on the inner weights 122 in the inner stack 129 are shifted 22.5degrees from each other. If alignment of the tabs 126 a and 126 b in thetop weight is assigned a reference angle of 0 degrees, then the secondinner weight from the top will have its tabs 126 a, 126 b aligned at22.5 degrees counterclockwise to the reference angle. The third weightis aligned at 45 degrees, and so on. Therefore, the seventh weight isaligned where the angle is 135 degrees.

[0052] Because two tabs 126 a, 126 b are used in each weight, and theseare 18 degrees apart, and if there is no eighth weight, the radial spacebetween the seventh tab and 180 degrees is unused by any of the sevenweights.

[0053] Each pair of lift pins 144 a, 144 b (hidden under the tabs in thetab-ring 125) can engage one and only one of the tabs 126 a, 126 b asthe selector rotates between 0 and 135 degrees. If the selector is setat 157.5 degrees, none of the weight will be engaged.

[0054] Bearing in mind that any weight selected carries with it all theweights above it, it is clear that by rotating the selectors 141, 150any one of the weights 121, 122 can be selected.

[0055] An advantageous arrangement for the weight stack 101 is obtainedif the outer weights 121 are 40 lbs. each, and if the inner weights 122are 5 lbs. each. This arrangement allows a user to select any weightbetween 0 and 315 lbs., in 5 lbs. increments (ignoring the weight of theplate 113 and associated hardware, such as the selectors 141, 150).

[0056]FIG. 8 shows the stack 101 with the first or top outer weight 121selected, as well as the top two inner weights 122. FIG. 9 shows thestack 101 with the top 5 outer weights selected, as well as the top 6inner weights 122.

[0057] As shown in FIG. 4 and FIG. 5, the selector 150 is positioned onthe guide rod 112 and is rotatable around bushing 116 (at the top) andbushing 162 (at the bottom). These bushings 116, 162 allow smoothvertical motion of the selector 150 on the stationary guide rod 112, aswell as low-friction rotation of the selector 150 with reference to theguide rod 112.

[0058] The bottom bushing 162 is designed to fit into and engage a dogclutch 152 . Thus when the selector 150 is at rest and is not pulled upby the lift plate 113, it is locked rotationally by the dog clutch 152.In this condition, the weights rest on stop pins 159 attached to theframe 158. To reduce friction, the bushing 162 is coupled to the frame158 through a ball bearing 156, although other arrangements may be used.For example, ball bearing 162 may be replaced by a low friction bushing.

[0059] The dog clutch 152 is coupled to a sprocket 153 which in turn isengaged to a worm gear 154. Worm gear 154 is mounted on a drive shaftattached to an electric motor 155. Thus, the sprocket 153 is driven bythe motor 155 through the worm gear 154 to rotate in reference to theguide rod 112.

[0060] The electric motor 155 is adapted to turn the selector 150 freelythrough a full rotation, or more, without encountering any resistanceother than the friction of the sprocket 153, the bushing 116, dog clutch152 and the ball bearing 156. Thus, while the selection is being made,none of the weights in the weight stack apply any force on the selector.Because the selection is “weight-free,” small stepper motors may beused. This not only decreases overall size and weight of the machine asa whole, but also decreases costs. Selector 141 for the outer weights issupported in an identical manner and is rotatable by a separate motor160 (shown in FIG. 10).

[0061] It should be noted that the motor, worm gear and sprocket arelocated in a position wherein these components are not moved, i.e., theyare not lifted, as the weights are raised or lowered. Thus, there is noneed for the motor to be mounted on the weights which is oftendeleterious to motor operation over many repetitions of the machine.

[0062] Thus by rotating the selectors 141 and 150 one pair of lift pins144 on each selector is placed under the lift tabs 126 a and 126 b ofone of the weights 121, 122. The selected weight(s) and all weightdisposed upon the selected weight(s) from the weight stack 101 arecoupled to the lift plate 113 through the respective selector 141 or150. When a user pulls on the cable 110, the lift plate 113 and theselected weight(s) of the weight stack 101 are raised and loweredthrough an exercise cycle.

[0063] The desired weight of the weight stacks 101 and 121 are selectedin each stack by placing the selector at the desired rotational angle.This is achieved by energizing the electric motors 155 and 160 that areassociated with each stack 101 or 129 for the proper length of time, sothat each motor moves from its current position to the new position.

[0064] The motors 155 and 160 in one implementation are servo motorsthat receive control signals indicating an amount of rotation necessaryto select the desired weight from the weight stacks. The application anddesign of servomotors for such uses as shown are well known in the artand not discussed further.

[0065] In a preferred implementation, the motors 155 and 160 are steppermotors such as model Z26440-12 manufactured by Haydon Switch andInstrument, Inc. This motor rotates 7.5 degrees for each pulse itreceives. With the worm gear reduction set at 1:40 gear ratio, 120pulses are required to rotate the sprocket 153 by 22.5 degrees. It isthus a simple matter to those schooled in the art of electronic controlcircuits to provide an electronic controller that will position each ofthe two selectors 141 and 150 at the desired weight selection.

[0066] The selector 150 and the indexing sprocket 153 are lockedrotationally only when the selector 150 is resting against the sprocket153.

[0067] With reference to FIG. 5, sensor 161 is a proximity sensormounted through bracket 162 mounted on frame 158. The proximity sensor161 is positioned so that it is within 5 millimeters from the bottom ofthe bushing 163. In particular, the proximity sensor 161, such as aproximity photo-microsensor EE-SB5 from Omron Electronics LLC, providesan output when a reflecting surface is within 5 millimeters from theface of the sensor. When the selector 150 is seated against the indexingsprocket 153, the lower bushing 163 is lined up with the position sensor161. When the selector 150 is pulled up from its rest position, thebushing 163 is disposed away from the sensor 161 and the output of thesensor 161 indicates to the control circuitry (not shown) that theselector 150 is not in place and that the motor 155 should not beactivated.

[0068] By placing a notch in the lower bushing 153 at a height that isaligned with the position sensor 161 when the selector 150 is at itsrest position against the indexing sprocket 153, the “home” position ofthe sprocket 153 can be detected by the position sensor 161. When thestepper motor 155 rotates the sprocket 153, the output of the positionsensor 161 is monitored. As the notch passes in front of the sensor 161,the reflection from the surface of the bushing 163 is momentarilyreduced due to the groove in its surface. The controller detects thischange in the output of the position sensor 161, and the “home” positionis confirmed. The sensing of the “home” position is useful to preventcumulative errors between the controller and the actual position of thesprocket 153.

[0069] A single-cable pull exercise system is inherently imbalanced.Because the ratio of the weights selected in the two stacks can be anycombination of weights, it is not possible to locate the hook 114 toprecisely compensate for this imbalance. In order to allow for a smoothoperation of the weight stack, the bushings 116, 163 act to prevent theplate 122 from tilting under such imbalance conditions.

[0070]FIG. 10 shows diagrammatically the electronic control unit 102 ofthe exercise machine of this invention. The control unit 102 isconnected to the exercise machine 100 to provide selection signals tothe motors 155 or 160 to select the desired weight from the weightstacks as described above. The position sensors 161 associated withselectors 141 and 150 transmit the position signals 215, 220 to thecontrol unit 102 indicating the “home” position and “rest” position ofeach selectors 141 and 150.

[0071] The control unit 102 includes a microprocessor to receive theposition signals 215 and 220 and generates encoded signals required toselect the desired weights from the weight stacks. The microprocessor200 contains a memory or storage device to retain an exercise regimenfor one or more users. The microprocessor 200 is connected to motordriver 205 which receives from the microprocessor the encoded signalsdesignating the weight to be selected. The motor driver 205 processesthe encoded signals and generates the respective selection signals 225or 230 that drive the motors 155 and 160 to select the desired weights.The selection signals 225, 230 cause the motors 155, 160 to rotate theselectors 141, 150 to place one pair of lifting pins 142 under thelifting tabs of the desired weight. Once a weight is selected in thismanner, pulling on that weight automatically lifts all the other weightsdisposed that particular weight in the respective stack. It should beappreciated that the nesting of the two sets of weights allows thedevice to select one set of weights from each stack independently.

[0072] The physical interface to the user is the user control panel 103.The user control panel 103 as shown is exemplary. Generally, the controlpanel 103 has a keypad 235 or keyboard to act as an input device, suchthat the user can provide the desired weight amounts or program anexercise regimen. The control panel 103 has a display 240 (a three digitalphanumeric display in this example) to indicate the weight amount orregimen step.

[0073] In operation, the user enters the desired weight on the keypad235. The display 240 shows the value of the weight just entered, in aflashing mode, while the motors 155 and 160 move the respectiveselectors to the desired positions. Once the selectors have reached thedesired positions, the display 240 stops flashing.

[0074] The three LED's 242, 244, 246 in the user control panel 103 areused to provide feedback to the user as to the status of the machine.The green LED 246 is lit when the machine is ready to be used forexercise. The yellow LED 244 is lit while the motor 155 and/or 160 isstepping the selector to a new setting or whenever one of the selectorsis not in its rest position. The red LED 242 indicates an internal faultin the machine.

[0075] The control unit 102 optimally may have a network interface 210to allow communication of the microprocessor 200 to a personal computer250 or with a communication network 255 such as the Internet. Thenetwork interface 210 allows updating of the program stored in thememory of the microprocessor. Alternately, the personal computer 250 orcommunication network 255 gives the necessary instructions to change theweights. This structure further allows a physical trainer or an expertsystem to direct and monitor multiple users through the networkinterface of multiple exercise machines.

[0076] It will be appreciated that the weight lifting machine providesnumerous advantages over the prior art. For example, it provides aweight stack that is compact, having a reduced footprint, yet one whichnonetheless provides a broad range of weight selection. Selection of theweight is precise and errors in selecting the weight are minimized. Theconstruction also provides smooth operation as the weights are raisedand/or lowered.

[0077] While this invention has been particularly shown and describedwith reference to the preferred embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made without departing from the spirit and scope of theinvention. For example, while the embodiment shown describes an exercisemachine in which weights are raised or lowered, it will be appreciatedthat the principles of the invention are applicable to other types ofexercise machines in which various weights are selected by the user.

[0078] One of the advantages of an electrically controlled weight stackis that the user may change the weights from different locations aroundthe machine. In multi-function exercise machines, for example, the usermay use a “lat” pull down where he faces the weight stack, and thenswitch to a leg extension where he faces away from the stack. As theexercise sets proceed, weights need to be changed (usually increasedafter each set), which would require getting up from the seat andreaching for the weight-selecting pin in a mechanical weight machine.

[0079] It will be appreciated that the electronically controlled machineof the present invention advantageously may allow the use of a portabledisplay/keypad that may be moved with the user, thus making the weightselection within reach at all times. Optionally, an RF link may be usedbetween the display and the controller of the exercise machine. Suchtechnology is readily available and can be used to replace a wirednetwork, although it is contemplated that further advances in thistechnology will make such linkages even smaller (and perhaps worn by auser as a watch-like display) in the future.

We claim:
 1. An exercise machine comprising: a substantially verticalguide rod; a set of weights arranged in a vertically stackedrelationship and movable along said guide rod; a motor-driven selectorhaving a plurality of positions, said selector being arranged andconstructed to engage only one of said weights in each position; a motorcoupled to said selector, said motor being arranged to selectively shiftsaid selector between said positions thereby selecting said number ofweights, while at the same time not being mounted to be carried by theweights; and a lifting member having a distal and a proximal end, saiddistal end being coupled to said weights to lift a number of saidweights as determined by said selector when a force is applied to saidproximal end.
 2. The machine of claim 1 wherein said weights are alignedto define a passageway and said selector is disposed in said passageway.3. The machine of claim 2 wherein each said weight has a couplingelement extending into said passageway and said selector is adapted toselectively engage said coupling element.
 4. The machine of claim 3wherein the coupling elements are offset for each weight, with eachweight being uniquely associated with coupling elements havingpredetermined angles.
 5. The machine of claim 4 further comprising acontrol unit in communication with the motor to transmit a selectionsignal to the motor to shift said selector to select the number ofweights.
 6. The exercise machine of claim 1 wherein the selectorcomprises a sleeve placed so as to ride on said guide rod; an array oflifting pins placed on said sleeve to engage said coupling element; anda lifting plate coupled to the distal end of the elongated member andhaving an opening through which said sleeve is secured.
 7. The exercisemachine of claim 1 wherein the weights do not put a load on the motor asthe weights are selected.
 8. The exercise machine of claim 7 wherein themotor is a stepper motor.
 9. An exercise machine comprising: a pluralityof weights, said weights being stacked in a vertical arrangement anddefining a cavity extending through said weights, each weight having acoupling member extending into said cavity, said coupling members beingangularly offset from each other, said weights being movable verticallyalong a vertical axis; a motor-driven selector, disposed in said cavityand having a plurality of angular positions, said selector engaging onlyone of said weights in each said angular position; an elongated memberhaving a proximal end adapted to be held by a user and a distal endcoupled to said weights, wherein when the user applies a force on saidelongated member, a number of said weights are moved vertically, saidnumber being determined by the position of said selector; an actuatorcoupled to said selector, said actuator being adapted to move saidselector to one of said angular positions in response to commands, saidactuator including an electric motor adapted to rotate said selector toone of said positions in response to said commands, said electric motorbeing mounted as to not be carried by the weights.
 10. The exercisemachine of claim 9 further comprising a controller in communication withthe actuator to retain said commands and upon request transfer saidcommands to the actuator.
 11. The exercise machine of claim 10 whereinsaid controller has a keypad interface to receive said commands fromsaid user.
 12. The exercise machine of claim 11 wherein the controllerhas a network interface to receive the commands from an externalcomputing system.
 13. The exercise machine of claim 12 wherein thecommands detail an exercise regimen.
 14. An exercise machine comprising:a substantially vertical guide rod; a first set of weights arranged in astacked relationship and movable along said guide rod; a firstmotor-driven selector having a first plurality of positions, said firstselector being arranged and constructed to engage only one weight ofsaid first set of weights in each position; a second set of weightsarranged in a stacked relationship and movable parallel to said guiderod; a second motor-driven selector having a second plurality ofpositions, said secondary selector being arranged and constructed toengage only one of said secondary weights in each position of saidsecond plurality of positions; an elongated member having a distal and aproximal end, said distal end being coupled to said weights to lift afirst number of said first weights and a second number of said secondweights as determined by said first and second selectors when a force isapplied to said proximal end; a first stepper motor coupled to saidfirst selector, said first motor being arranged to selectively shiftsaid first selector between said positions thereby selecting said firstnumber, said first motor mounted as to not be carried by said first setof weights; and a second stepper motor coupled to said second selector,said second motor being arranged to selectively shift said secondselector between said positions thereby selecting said second number,said second motor mounted as to not be carried by said secondaryweights.
 15. The machine of claim 14 wherein said first set of weightsare aligned to define a first passageway and said second set of weightsis nested in said first passageway.
 16. The machine of claim 14 whereinsaid first and second sets of weights each define a first and secondpassageway, respectively, and wherein said fist selector is disposed insaid first passageway and said second selector is disposed in saidsecond passageway.
 17. The machine of claim 16 wherein each said weightsweight has a tab extending into one of said passageways and each saidselector is adapted to selectively engage said tab.
 18. The machine ofclaim 17 wherein the tabs of each set are angularly offset with eachweight of each set being associated with a corresponding angular tabposition.
 19. The machine of claim 18 further comprising a control unitin communication with said motors to transmit a selection signals toeach said motor to select said first and second numbers.
 20. Theexercise machine of claim 14 further comprising a lifting plate coupledto the distal end of the elongated member and a coupling memberconnecting said plate to said selectors.
 21. The exercise machine ofclaim 14 wherein the primary and secondary selectors comprise: a sleeveplaced riding on said vertical guide rail and secured in an openingthrough; and an array of lifting pins placed on said sleeve toselectively engage said coupling element.
 22. The exercise machine ofclaim 14 wherein weights do not put a load on the stepper motors as theweights are selected.
 23. An exercise machine comprising: asubstantially vertical guide rod; a set of weights arranged in avertical stacked relationship and movable along said guide rod; aselector having a plurality of positions constructed to engage only oneof said weights in each position; a lifting member having a distal endand a proximal end, said distal end being coupled to said weights tolift a number of said weights as determined by said selector when aforce is applied to said proximal end; and a control panel forcontrolling the selector, said control panel being remote from the restof the machine.
 24. The machine of claim 23 wherein the control panel isconnected to the rest of the machine by a cable.
 25. The machine ofclaim 23 wherein the control panel is connected to the rest of themachine by an RF link.